1. Field of the Invention
This invention relates to a collision avoidance warning device, more particularly to a vehicle collision avoidance system implementing a fuzzy logic based vehicle collision avoidance warning device.
2. Description of Related Art
In the modern society, owing a vehicle is not a difficult task because the retail price of vehicles is going down and consumer""s spending power is going up. As a result, the number of vehicles on the road rapidly increases. Since more vehicles on the road, more accidents are bound to happen. In the past, the driver judges the distance between his/her vehicle and the vehicle in front by human vision and accordingly brakes or performs some recovery maneuvers for preventing danger caused by vehicle collision. However vehicle collisions continue to happen because human cannot accurately determine distance or human sometimes make careless mistakes. Therefore, the method of monitoring the driver cannot effectively avoid danger. Recently, the development of vehicle warning system is to compensate for human inability.
There are already solutions to the above problem such as U.S. Pat. No. 5,699,040, which suggests a vehicle collision preventing system. This system determines the possibility of collision according to the distance between the travelling vehicle and the target vehicle (including lateral and longitudinal distances). A xe2x80x98Kxe2x80x99 value is obtained by measuring the lateral relative distance and the friction coefficient to determine the safety braking distance.
Based on the above method, the lateral relative distance cannot be accurately obtained. Moreover, the road friction coefficient must be obtained from a sensing device located in the tire, which adds to manufacturing cost of the system. If the appropriate coefficient is deviated, the safety braking distance will be affected.
Furthermore, U.S. Pat. No. 5,521,580 suggests a danger avoidance system for a vehicle, which tests the driver""s awareness to danger and when the driver is not aware of danger, the system will activate the danger avoidance system. The system comprises an ambient condition monitoring system, a vehicle monitoring system, and a driver monitoring system to activate travelling condition deciding and danger recognition confirming.
Based on the above method, if the driver monitoring system fails, travelling condition deciding and danger recognition confirming cannot be activated. The driver monitoring system consisting of 15 sensing devices to measure temperature, blood pressure etc . . . is expensive and causes inconvenience to the driver. Assume if the driver is carelessly lazy, the driver monitoring system might mistakenly judges the condition of that the driver has been aware of danger such that the danger recognition confirming cannot be activated.
Furthermore, Republic of China Patent Number 134625 suggests a method of using formulas to calculate the distance between the travelling vehicle and the vehicles in front and behind. The disadvantage of this system is the requirement of precise measurement of distance between the vehicles and it does not take into account the ambient and driver conditions. Moreover, this method is formula based, which cannot posses good robustness and disturbance rejection ability.
An object of this invention is a vehicle collision avoidance warning device, more particularly a fuzzy logic based vehicle collision avoidance warning device, which can reduce the number of sensing devices and also correct errors from the sensing devices.
Another object of this invention is a vehicle collision avoidance warning device, more particularly a fuzzy logic based vehicle collision avoidance warning device, which avoids using a complicated driver monitoring system.
Another object of this invention is a vehicle collision avoidance warning device, more particularly a fuzzy logic based vehicle collision avoidance system, which does not require a precise distance measurement and has high flexibility and ability to withstand interference.
In order to achieve the above objects, this invention provides a vehicle collision avoidance system, which comprises a sensing module that detects parameters of engine RPM (Rotation per minute), throttle opening, vehicle speed, and relative distance; a fuzzy logic controller coupled to the sensing module to receive the parameters of engine RPM, fuel throttle index, vehicle speed, and relative distance and generate a safety distance value using fuzzy logic; a safety warning indicator coupled to the fuzzy logic controller and sensing module to compare the relative distance with the safety distance value and generate a warning signal based on the comparison result.
The above sensing module further comprises an engine RPM sensing device for detecting the engine RPM of the vehicle, a fuel throttle sensing device for detecting the throttle input of the driver and output a throttle index, a vehicle speed sensing device for detecting the speed of the vehicle, and a distance sensing device for measuring relative distance.
The above fuzzy logic controller further comprises a differentiator that receives the relative distance signal and differentiate it to get a distance variation over time; an adjusting factor fuzzy logic inference module that receives the parameters of engine RPM, fuel throttle index, and vehicle speed to deduce an adjusting factor using fuzzy logic; a safety distance fuzzy logic inference module coupled to the differentiator to receive vehicle speed parameter and the output of the differentiator to deduce a safety distance using fuzzy logic; and a multiplier coupled to the adjusting factor fuzzy logic inference module and the safety distance fuzzy logic inference module to multiply the adjusting factor by the deduced safety distance to generate a safety distance value.
This invention provides a vehicle collision avoidance warning method. Firstly, the parameters of the vehicle such as engine RPM, fuel throttle index, vehicle speed, and relative distance are received. Following is to deduce a safety distance using fuzzy logic according to the obtained parameters of engine RPM, fuel throttle index, vehicle speed, and relative distance. A comparison of the safety distance value with the relative distance will generate a warning signal.
Furthermore, the fuzzy logic controller generates an adjusting factor according to the parameters of engine RPM, fuel throttle index, and vehicle speed. A deduced safety distance is obtained using fuzzy logic according to the vehicle speed and the distance variation during the time interval. The deduced safety distance is multiplied by the adjusting factor to generate a safety distance. When the relative distance is smaller than the safety distance, the warning signal is a danger signal. Otherwise, determine if the relative distance is greater than a predefined value. If the relative distance is greater than the predefined value, the warning signal is a safe signal, and if the relative distance is smaller than the predefined value, the warning signal is a caution warning.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.